Rotary heat pump

ABSTRACT

A heat-operated rotary heat pump is provided for use in air conditioning, particularly for cooling the passenger compartment of an automobile or other vehicle. It includes a generator, absorber, condenser, and evaporator, all mounted for rotation as a group. The device is capable of being made portable.

United States Patent 91 Pravda June 26, 1973 ROTARY HEAT PUMP [75] Inventor: Milton F. Pravda, Baltimore, Md.

[73] Assignee: Dynatherm Corporation,

Cockeysville, Md.

221 Filedz Dec. 11,1971

[21] Appl. No.: 209,178

[52] US. Cl. .Q. 62/476, 62/499 [51] Int. Cl. F25b 15/02, F25b 3/00 [58] Field of Search 62/476, 499

[56] References Cited UNITED STATES PATENTS 2,197,001 4/1940 Maidri n, 62/499 X 3,559,419 2/1971 Kantor 62/101 3,605,436 9/1971 Gammill, Jr. 62/499 X 2,229,500

1/1941 Goldsmith 62/499 X 3,456,454 7/1969 Kantor 62/476 X FOREIGN PATENTS OR APPLICATIONS 418,500 11/1924, Germany 62/499 136,061 12/1933 Austria 62/499 Primary Examiner-William F. ODea Assistant Examiner-Peter D. Ferguson Attorney-A. I-l. Caser [57] ABSTRACT A heat-operated rotary heat pump is provided for use in air conditioning, particularly for cooling the passenger compartment of an automobile or other vehicle. It includes a generator, absorber, condenser, and evaporator, all mounted for rotation as a group. The device is capable of being made portable.

21 Claims, 13 Drawing Figures PAIENTEBJIIIIZB I975 3. 740.966 sum 1 If 5 Mm P Pmmmmzs ma SIEMENS FIG.

ROTARY HEAT PUMP BACKGROUND OF THE INVENTION (1) The field of the invention comprises heat pumps for use in air conditioning. (2) In a conventional air conditioner, as for cooling a space, a fan blows air against a stationary evaporator containing a cold refrigerant, and the cooled air is delivered to the space. Another fan blows air against a stationary condenser containing heated refrigerant to cool the latter, which is then returned to the evaporator. A compressor takes expanded refrigerant from the evaporator and delivers it, in compressed form, to the condenser. Both fans and the compressor, it will be noted, are driven by electric motors, and power consumption, particular for the compressor motor, is high. The system is generally criticized as having poor heat transfer efficiency, as occupying too large a space, and as noisy, and in response to these criticisms, a rotary system has been suggested comprising an evaporator, a condenser, an expansion valve therebetween, a compressor, an electric motor for the compressor, and an electric motor for rotation. Here also high power costs for operating the compressor are involved, and if the rotary system is used in an auto, the power drain on the engine represents a disadvantage. For portability, the rotary system would require such large batteries as to nullify the advantage of portability.

Over the conventional stationary system, the invention enjoys the above-described advantages of the known rotary system, being more compact and less noisy, and having better heat transfer efficiency, while over the said rotary system it provides an economy in both construction and operation by omitting a compressor and by its capability of being portable; furthermore, it dispenses with the seals required in the rotary system, and it operates at lower pressures, enabling thin walls to be used in its construction, and affording a substantial reduction in weight and size. Thin walls also promote good heat transfer.

SUMMARY OF THE INVENTION The rotary heat pump of the invention comprises a plurality of enclosed interconnected units or chambers mounted for rotation as a group, and as a group being airtight and liguidtight. A refrigerant liquid is used which undergoes evaporation and condensation, these processes taking place at two pressure levels, but instead of a compressor for obtaining the different pressures, a heat-operated generator and an absorber are used. Heat, rather than an electrically driven compressor, thus supplies the energy, for the most part, for operation, and the invention is specially adapted to employ waste heat,such as radiator heat or that from hot exhaust gases of an auto, or even heat obtainable by burning low cost hydrocarbons or other fuels. The in,- terconnected units or chambers include a generator, as noted, in which the refrigerant is separated by heat into vapors and a concentrated liquid fraction; a condenser in which the vapors are condensed, thereby releasing heat of condensation; an evaporator for vaporizing the condensed vapors, thereby absorbing heat of vaporization and cooling the evaporator walls; and an absorber, noted above, wherein the concentrated liquid fraction is used to absorb the vapors from the evaporator, thereby producing the original refrigerant for reuse. A fan moves air against the cold walls of the rotating evaporator, and the thus cooled air is available for cooling a desired space.

A special advantage of the invention is its capability of being made very small, or miniaturized, as illustrated by FIG. 12. Miniaturization is difficult to bring about in systems using a compressor.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is illustrated in the following drawings, which are diagrammatic, and in which FIG. 1 is a longitudinal view of the device, partly sectioned to show the interior construction;

FIG. 2 is a view, partly in section, of what may be termed the pump and spray assembly which is used in the device of FIG. 1;

FIGS. 3-7 are, respectively, partial sectional views along lines 33, 4-4, 55, 66, and 7-7 of FIG. 1;

FIG. 8 is a view of apparatus for introducing refrigerant into the device of FIG. 1;

FIG. 9 is a simplified view of the deviceof FIG. 1 but showing modifications;

FIG. 10 is a simplified partial view of the left hand portion of FIG. 1 but showing a modification;

FIG. 11 is a simplified partial view of the right hand portion of FIG. 1 showing an alternative construction in dashed lines;

FIG. 12 is, in simplified form, a view like FIG. 1 but showing a modification in the form of a miniaturized air conditioning device; and

FIG. 13 is a simplified view of another modification.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS Referring to FIG. 1, there is shown a rotary air conditioning apparatus, or heat pump, for cooling a space comprising a plurality of enclosed interconnected cylindrically-shaped units or sections or chambers mounted for rotation as a group. By enclosed is meant that the chambers have lateral cylindrically shaped walls and the two end chambers are closed off by end walls, although as between one another the chambers, though separate, are interconnected. The chambers comprise a generator 10, absorber 11, condenser 12, evaporator 13, and a liquid cooler 14, and as a group they are hermetically sealed, being airtight, vaportight, and watertight.

Generator 10 is defined by the lateral cylindrical walls 15 and the plates or discs 16 and 17; absorber 11 is defined by the lateral walls 15, plate 17, and the disc 18; condenser 12 by the laterals walls 19, disc 18, and plate 20; evaporator 13 by the lateral walls 19, plate 20, and the end wall 21; and the liquid cooler by the walls 15, plate 16, and end wall 22.

Extending between the generator 10 and absorber 11, and also projecting into the liquid cooler 14, is an assembly 25, note FIGS. 1 and 2, which includes pump and spray means. This assembly comprises a substantially non-rotating hollow pipe 26 having closed ends at 27 and 28 but which is providedwith an inlet and an outlet adjacent such ends. Pitot tube 29, note also FIG. 7, comprises the inlet, being connected to the portion of pipe 26 in the liquid cooler. On the portion of the pipe in the generator there are provided means in the form of counterweight 30, note also FIG. 6, for maintaining the pipe in a substantially non-rotating disposition. The counterweight, which is kept out of contact with the liquid in the generator to avoid drag, is joined to the pipe by a neck 31. The pipe outlet comprises spray means on that portion of the pipe in the absorber 11, comprising a fan 32, note FIG. 5, surrounding one or more discharge tubes 33, the latter being connected to the pipe. Spray is formed by the discharge of liquid refrigerant from tube 33 onto the blades or vanes 39 of the rotating fan. Pipe 26 is supported on bearings 34, 35 disposed in central apertures in the plates 16, 17, respectively.

Fan 32, note FIG. 5, comprises a disc 38 to which are attached a series of circumferentially arranged vanes 39 which extend toward the left, looking at FIG. 1. The fan is supported on the circumferentially arranged vapor-conducting tubes 40-47 which extend between plate 17 and disc 18 and which extend through disc 38 of the fan. It will be seen that these tubes place the generator in communication with the condenser 12. Disc 18 has a central aperture 48 in which there is fixedly secured, as by a press fit with or without an added weldment, an open-ended cylinder 49 which extends the length of condenser 12 and which at its other end is fixedly secured to plate 20. Cylinder 49 thus places absorber 11 in communication with evaporator 13.

Absorber 11, condenser 12, evaporator 13, and liquid cooler 14 are each provided with external fins or fan blades 50, 51, 52, and 53, note FIGS. 1 and 3-7. At the right hand end of the apparatus there are means for driving the chambers as a group comprising the pulley set 54 disposed on the shaft 55 which is fixed to the end wall 21. Means for supporting the shaft for rotation are present at 56, comprising a bearing, and another bearing 57 supports the opposite shaft 58, the latter comprising a hollow pipe which functions as the filling line, having therein a valve 59 and a closing cap 60.

It may be seen that the lateral walls cover three chambers: the liquid cooler, generator, and absorber. Such walls, with the end wall 22, actually comprise a single cylinder which is closed at one end by wall 22 and which at its open end 63 is provided with a flange 64 fixed thereto. Similarly, the lateral walls 19 with the end wall 21 comprise another cylinder which is closed at one end by wall 21 and open at the end 65 and which is provided with a fixed flange 66. The assembly 25, note FIG. 2, is conveniently put together first, then inserted in the first cylinder until disc 18 abuts the flange 64, and then the second cylinder is placed over the right hand end of assembly so that its flange 66 abuts disc 18. It will be understood that bolt holes, note 67 and 68 of FIG. 1, will have been drilled in the flanges and disc, and that the parts may be alined by means of dowel pins. With the parts alined, they may be secured with the bolts and nuts, as shown.

To produce a tight seal, O-rings 61 and 62 are provided in appropriate grooves on opposite sides of the disc 18, and these rings may be lubricated beforehand as with a water soluble vacuum grease.

Liquid refrigerant may be added to the device at the left hand end by removing the cap 60 from line 70, attaching to the latter a union 71, note FIG. 8, and then by means of the union connecting the filling equipment shown in FIG. 8, comprising funnel 72, valve 73, valve 74, pump 75, and evacuation gauge 76, together with the connecting lines shown. A sight glass 77 may conveniently be present in line 78. With valves 59 and 74 open, and valve 73 closed, the vacuum pump 75 is started and the system evacuated for about 16 hour to produce a hard vacuum sufficient to remove substantially all air and non-condensable gases. The pressure in the evacuated system is preferably less than 1 micron of mercury, and may be less than 0.0l, or 0.001, or even 0.0001 micron of mercury. Then with valves and 74 closed, refrigerant liquid is added to funnel 72. Precautions are taken to eliminate all air that may become trapped above valve 73 and below the funnel. Valve 73 is then slowly opened and also valve 59, and one may observe that the level of refrigerant in the funnel slowly drops. As the refrigerant is slowly forced into the device by the pressure of air over the refrigerant in the funnel, the operator is careful to avoid any entrainment of air, and to avoid having the refrigerant level pass below the sight glass 77. When the desired amount of refrigerant has been added to the device, valves 59 and 73 are closed. The fill assembly may then be disconnected at union 71, and cap 60 replaced to prevent any possible in-leakage of air.

A preferred refrigerant is an aqueous solution of the neutral salt lithium bromide, LiBr. This salt is a white deliquescent solid having a dry density of 3.464, a melting point of 547C, and a boiling point of 1,265C. As indicated, it absorbs water, and when it absorbs enough water to form a mixture containing about 30 percent water, the mixture becomes liquid. Preferably, aqueous solutions containing 50 to 65 percent by weight of dissolved lithium bromide are used herein, these concentrations prevailing initially, i.e., before rotation and heating are started, and it may be noted that within the foregoing range higher concentrations, say 57 to 65 percent, are more preferred. Even higher concentrations, i.e., above 65 percent, are suitable provided that in the generator the refrigerant is always in the liquid state, and provided that elsewhere the solution is in a suitably flowable state; thus, in the liquid cooler the solution should not be so viscous as to hinder its capacity to be passed to the absorber and effectively sprayed.

The operation of the device may be set forth briefly, using an aqueous solution of lithium bromide as the refrigerant. With refrigerant solution charged to the device, as described, the solution initially will flow from the chamber 14 into the generator 10 through the aperture 80, note FIGS. 1 and 7, in the plate 16. Several additional circumferentially spaced apertures 81, 82, and 83 are shown in FIG. 7, and it will be understood that as many as desired may be present, not only in plate 16 but in the other apertured plates to be described. It will be noted that the apertures are adjacent the periphery of the plate 16, although they may also be in the periphery itself, and if desired, one may use as apertures the ordinary clearances between the plates and the shells 15, 19, this last construction tending to minimize the thickness of the liquid hugging the cylindrical walls of the chambers. From chamber 10 the refrigerant initially will also flow into the absorber 11 through the aperture 84 of plate 17, note also FIG. 6 where additional apertures 85, 86, and 87 are shown. Thus, initially, i.e., before heating of the device is begun, and especially after rotation is started, the refrigerant will distribute itself equally throughout chambers 14, 10, and 11. The refrigerant levels shown in these chambers in FIG. 1 are not shown as all equal because, as described below, FIG. 1 represents the device in steady state operation.

The device is rotated by connecting pulley 54 through a conventional driving belt, not shown, to an electric motor, also not shown. Illustrative rotational speeds are 1,500 to 2,700 r.p.m. Generally speaking,

the speed is proportional to the size of the device, higher speeds being used for smaller devices and lower speeds for larger devices. When the device is rotating at constant speed, heat is applied to the external surfaces of the generator, either to part or all of such surfaces, using any suitable heat source, including a hydrocarbon torch with propane, butane, and the like hydrocarbon as fuel, or an electrical heating coil may be wound around such surfaces. It is also feasible to flow hot waste gases over the surfaces by any suitable means, particularly hot exhaust gases of an internal combustion engine. Solar heat is feasible. For a portable device, a suitable heat source is a simple propane burner, and as this is applied to the generator external surfaces, the operator can touch the external surfaces of the evaporator 13 to ascertain when cooling is being effected. He can then adjust the rate of propane burning to produce continuously a desired degree of cooling. These actions of the operator can, of course, be eliminated by using automatic controls, whereby settings are made automatically and the device can adjust itself to accomodate variations in temperature.

During heating, it is considered that in the generator the aqueous refrigerant is partly vaporized, producing vapors and leaving a concentrated liquid fraction, indicated at 95 in FIG. 1, in centrifugal movement on the cylindrical wall of the chamber. The vapors or vapor fraction, comprising water vapor, pass into the tubes 40-47, which open into chamber 10 through the plate 17, and emerge in the condenser 12 on the other side of disc 18. No lithium bromide leaves the generator with the vapor fraction. Because the pressure in the generator is higher, owing to the application of heat, the level of refrigerant, at steady state operation, tends to be smaller, as indicated at 95, than that in the liquid cooler or the absorber.

In condenser 12 the temperature is lower than in the generator and the vapors are condensed, accumulating on the wall of the chamber as at 96. Heat of condensation is produced and is dissipated by the external fins 51. As the level builds up, condensed vapors leave the condenser through peripheral openings in the plate 20, one of which is shown at 97 of FIG. 1 and others at 98, 99, and 100 of FIG. 3, and enter the evaporator 13. In the latter, the pressure is lower than in the condenser, as will be discussed, and hence the liquid level tends to be greater than in the condenser, as compare the level 101 with 96. Furthermore, owing to the lower pressure, condensed vapors in the evaporator are vaporized, and the resulting vapors pass to absorber 11 via the cylindrical passage 49. Heat of vaporization is thus removed from the environment, and the walls 102 and outer surfaces 103 of the evaporator become cooled. As air moves past the rotating surfaces of fan 52, it is cooled, and the fan moves this cooled air toward the space to be cooled. Note that the air moving past the rotating surface of fan 52 has a higher velocity than if the air were blown against a stationary cooled surface. The fan 52 is constructed of a good heat-conductive material, such as copper, so that heat may flow efficiently to the rotating external surfaces 103 of the evaporator.

As may be obvious, the temperature should not drop below the freezing point of the refrigerant.

In absorber 11 the vapors from the evaporator meet and are absorbed by a fine spray of the concentrated refrigerant liquid. The spray is brought about by the fact that in the liquid cooler 14 the pitot tube 29 picks up original refrigerant; that is, the chamber 14 and the refrigerant 105 therein are rotating, whereas the pitot tube is more or less stationary, so that refrigerant passes through the open end 106 of the tube, which is immersed therein, and then into the hollow pipe 26 to the discharge outlet 33, from which point it is sprayed throughout chamber 11 by the vanes 39 (FIG. 5) of the rotating fan 32. To aid the spraying action, one or more nozzles may be used in place of outlet 33. The tube 29 is substantially stationary because of the influence of the counterweight 30, which permits pipe 26 to remain substantially stationary on the rotating bearings 34, 35. These bearings rotate with the lateral walls 15 and 19 and with the plates 16 and 17, disc 18, and plates 20 and 21. The fan 32 rotates because its disc 38 is engaged by the tubes 40-47, which rotate with their supporting plates 17 and 18.

Pitot tubes, as is known, are conventionally used to measure pressure heads in moving liquids. Here, the velocity head developed by the rotating liquid is made use of, and by maintaining the pitot tube substantially stationary, the velocity head is converted into a flow. Such use of the pitot tube is advantageous in enabling liquid pumping to be carried out within a sealed rotating device without necessity of providing a vacuum tight rotating seal, assuming the latter to exist. The pitot tube may be of any suitable needle size and hole diameter.

Instead ofa pitot tube, one may use a scoop or scooplike member, or any other suitable structure, for picking up the liquid and transferring it to the absorber, but a pitot tube is convenient as well as effective and is therefore preferred. It will be noted that these various structures comprise an extension or extending member connected to the hollow pipe.

In absorber 11, the liquid therein tends to increase in volume because of the addition of water vapor by the absorption process. Owing to the attraction of the sprayed concentrated refrigerant for water vapor, the latter is, in effect, pulled from the evaporator 13 via cylinder 49, and this action tends to reduce the pressure in the evaporator. In turn, such reduction of pressure favors the vaporization of the liquid in the evaporator.

It will be appreciated that in the absorption process the refrigerant solution becomes diluted owing to the absorption of the water vapor coming from the evaporator.

As described in the next paragraph, the liquid level in the absorber can increase to a limited extent, as indicated by the level 108, and beyond this the liquid flows into generator 10 through the peripheral openings 84-87. From the generator the hot concentrated refrigerant passes into liquid cooler 14 through peripheral openings -83 where it mingles with original refrigerant introduced through pipe 58. The resulting mixed refrigerant thus tends to be more concentrated than the original and is in a desirable condition for the absorber; it is first cooled in the liquid cooler by the action of the external fins 53 and then is transferred to the absorber l 1 by the pumping action of pitot tube 29, as described. The cooling of this mixed refrigerant further enhances its efficacy in the absorber.

The reason why the liquid level in the absorber is higher than in the generator is because the pressure in the absorber is considerably lower than in the generator. The pressure in the liquid cooler is also less than in the generator, and this accounts for the higher liquid level in the cooler. And in the evaporator the pressure is lower than in the condenser and thus it has a higher liquid level. In this connection, it will be understood that the amount of refrigerant solution initially charged to the device will be sufficient for all requirements, including (l) the amount necessary to establish the pitot tube pumping action, (2) the amount necessary to permit vaporization of water in the generator, and (3) the amount necessary to establish peripheral seals between one chamber and the next whereby the various peripheral openings are covered by liquid. Owing to centrifugal action, the solution tends to cling to the internal surfaces of the cylindrical walls and 19 and to distribute itself as a uniform layer thereon. Any nonuniformites in the depth or thickness of such layer tend to be corrected automatically unless there is some barrier to this process of self adjustment. Such barriers do arise during operation of the device and consist in pressure changes. Initially, i.e., before the application of heat, the pressure (or vacuum) produced by the vacuum pump 75 (FIG. 8) obtains in all the chambers, but after rotation starts and the generator is heated, changes in pressure take place. In the generator, where vaporization of some of the water of the solution occurs, the pressure increases, and as a consequence the liquid level decreases. In the condenser, where vapors from the generator condense, the pressure is about the same as in the generator, and in consequence the liquid level decreases. Thus, the liquid level in each of the chambers reflects the pressure obtaining therein; or, in other words, there is an equilibrium set up in each chamber between the pressure and the liquid level. But in every case a seal is assured at the peripheral openings by having sufficient liquid present. As an example, when a chamber, let us say it is the absorber, receives more liquid than the described equilibrium permits, then, owing to centrigual forces, some of the liquid is forced to flow through the peripheral openings over to the generator, and such flow continues until the equilibrium is restored. The centrifugal movement of the chambers and liquid therein is, of course, a necessary part of the foregoing actions. As another example, note that in the liquid cooler the solution is always being pumped out by the pitot tube and therefore the liquid level tends to be less than that permitted by the prevailing pressure; in consequence, liquid from the generator flows into the cooler in amounts necessary to restore equilibrium.

Considering briefly the flow of solution and vapor, it may be seen that, starting with the generator, vapors flow to the condenser and are condensed, the condensed vapors then flow to the evaporator and are vaporized, and the resulting vapors flow to the absorber. In the latter, co'ol solution from the liquid cooler absorbs the vapors, the resulting dilute solution flows to the generator where it is concentrated, and then it flows to the liquid cooler. Looking at FIG. 1, one may note that the flow of solution is confined to the left of disc 18, and to the right of such disc only vapors and condensed vapors are present. The lithium bromide concentration of the solution changes as the solution flows between the generator and absorber, but it is to be observed that such concentration adjusts itself to provide good absorber efficiency. The solution is more concentrated when it enters the absorber and is thus more efficient to absorb the water vapor.

As to the flow of heat, it is apparent that heat is applied to the generator and, with the rotation, supplies the driving force which moves the solution, vapors, and condensed vapors along their courses. Heat is rejected in the absorber as heat of absorption; in the liquid cooler as sensible heat; and in the condenser as heat of condensation; and it is dissipated by the external fins present on these chambers. Heat is absorbed in the evaporator, producing the described cooling effect, and the external evaporator fins distribute this effect in the form of cooled air.

The preferred refrigerant solution, as described, is lithium bromide in water, in the concentrations noted. Other, preferably deliquescent, solids may be used in place of the lithium bromide, such as lithium molydbate, lithium chlorate, lithium di-hydrogen phosphate, lithium sulfide, potassium acetate, potassium carbonate dihydrate, potassium fluoride, potassium formate, potassium molybdate, potassium pyrophosphate, potassium propionate, potassium monosulfide, ammonium dibromoiodide, ammonium iron chloride, calcium chloride, cesium chloride, cesium iodide, chromium chloride, cobalt bromide, cobalt chloride, ferrous chloride, magnesium bromide, manganese chloride, sodium bromide, sodium hydroxide, and the like. The solid chosen should not boil over in the generator and should be stable to heat and in solution. Other solvents for the solid may be used in place of water, such as alcohols like methanol, ethanol, propanol, butanol, pentanol, and the like; ethers like diethyl ether, etc.; ketones like acetone, methyl ethyl ketone, and higher ketones; esters like ethyl acetate, etc.; hydrocarbons like ligroin, benzene, etc.; chlorinated hydrocarbons like chloroform, etc.; and alkanoic acids like acetic acid, propionic acid, and higher acids. Alkylene glycols like ethylene glycol and glycerol are suitable. Desirably, the solvent has physical properties, including vapor pressure characteristics, melting point, boiling point, latent heat of vaporization, etc., which are not too different from those of water, although solvents that freeze at temperatures below 32F such as methanol, chloroform, etc., would permit the device to be operated below the freezing point of water. The solid used should of course be soluble in the solvent. Deliquescent liquids may be useful in place of deliquescent solids.

The refrigerant may also comprise a solution of a hygroscopic solid or liquid in water or other suitable solvent, such solid or liquid being one that does not boil over in the generator and is stable to heat and in solution. Also useful as refrigerant is an aqueous solution of ammonia, and in this case the device will be operated under pressure.

The invention as described to this point may be illustrated by the following example.

EXAMPLE The apparatus of FIG. 1, after having been cleaned interiorly and dried, was assembled as shown, using a pitot tube of 0.022 inch hole diameter. Thermal insulation was used on plates 16 and 17 to help avoid heat flow from the generator to the liquid cooler and absorber. The cap 60 at the left end of the fill valve 59 was removed and an evacuation and fill assembly, note FIG. 8, was connected to such valve. Valves 59 and 74 were opened, and valve 73 closed, and the evacuation pump 75 started. Pumping was continued for about one-half hour, at which time the precision evacuation gage 76 gave a reading of about 29.5 inches of mercury (750 mm. mercury), which was sufficient to remove substantially all air and non-condensable gases. Pumping was stopped, and valves 59 and 74 closed.

An aqueous solution of lithium bromide, LiBr, was prepared by adding solid purified lithium bromide (Fisher Scientific Co. L 117) to distilled water until the resulting solution had a density of 1.585 g/cc. It contained 48-50 percent by weight of the salt. For a solution amounting to 220 cc (the amount charged to the device exclusive of that remaining in the filling apparatus), there were present about 168 cc water and the balance lithium bromide. The solution was poured into funnel 72. Any trapped air between valve 73 and the funnel was removed by tapping, and then valve 73 was slowly opened, as was valve 59. The solution level in the funnel was observed to decrease slowly as solution was forced into the device by air pressure. At no time was solution allowed to descend below the sight glass 77 in line 78. When no more solution entered the device, valves 59 and 73 were closed. The evacuation and fill assembly was disconnected at the outboard side of valve 59, and cap 60 was put back to prevent possible ingress of air.

Next, pulley 54 at the right end of the device was connected through a belt to an electric motor-operated driving pulley and the motor started at a speed setting of 2,200 r.p.m. Heat was applied to the underside of the generator, using a propane burner adjusted to burn at a low rate. After 3 to 5 minutes of applying heat, the surfaces of the evaporator 13 felt cold to the touch. At this point the following surface temperatures were measured with a contact thermocouple instrument and are reported with the corresponding internal pressures and the dimensions of the various chambers:

Dimensions lntemal lnside Chamber Temp. Pressure Diameter Length F. mm Hg inches inches Liquid Cooler 110 11.1 3.26 3.87 Generator 165 49.1 3.02 3.87 Absorber 110 11.1 3.02 3.87 Condenser 100 49.1 3.26 3.87 Evaporator 55 11 1 3.02 6.0

Room temperature during the run was 78F. lt may be noted that water at 55F. and 1 1 mm mercury pressure will boil, and will continue to boil until the pressure increases above 11 mm or until the temperature drops below 55F.

To evaluate the effectiveness of the device, the actual coefficient of performance, CP,,, was calculated from the equation, CP =Q,./Q,,, where Q, is the heat absorbed in the evaporator and Q, the heat absorbed in the generator. Q, was calculated to be 9.15 BTU/min. and Q, to be 23.33 BTU/min. The CP, therefore was 0.392, which means that for every BTU put into the device as heat, 0.392 BTU would be taken out of the air in the process of cooling. On On the basis of the temperatures noted in the table, the ideal CP was calculated to be 1.01.

While lower pressuresare preferred, as described, the device is operative at the pressure listed in the example. What is important, in this connection, is that substantially all air and non-condensable gases shall be evacuated, and this result was substantially obtained in the experiment.

In the example, it is considered that the actual CO could be improved over the value 0.392 by conserving the heat dissipated in the liquid cooler, as by adding such heat to the solution flowing from the absorber to the generator; or by operating the generator at a higher temperature; or by operating the absorber at a lower temperature. The last-noted step is conveniently achieved, as by sending a cooler solution from the liquid cooler to the absorber; or by using larger external fins on the absorber; or by using internal fins in the absorber (note 110 in FIG. 5 and note FIG. 9) to increase the contact area and improve the cooling action; or by spraying the solution to get finer drops, as by using spray nozzles at 33, thus increasing the time during which the drops are exposed to the water vapor; or by using a more concentrated refrigerant solution initially; or by combining two or more of the foregoing changes. For example, if the absorber temperature is reduced from 1 10 to F., the evaporator will reject approximately 38 BTU/min, which is more than four times the value in the example, and the actual CP would be 0.66 instead of 0.392. Actual CPs of up to 0.70 or 0.80 are considered to be obtainable by adopting the quite ordinary steps or changes noted immediately above.

In the example, it will be noted that the evaporator is longer than the chambers. This is a construction designed to provide more cooling area; however, the device is operative when the evaporator length is the same as, or even less than, that of the other chambers. Nor need the lengths of the chambers all be the same. It will also be noted in the example thatthe diameter of the liquid cooler and of the condenser is slightly larger than that of the other units; such construction is a preferred one. By having the liquid cooler somewhat larger in diameter, there results an advantage in that the solution tends to remain longer in the cooler and thus to cool over a longer time and to a lower temperature. As noted, it is desirable to send a cooler solution to the absorber. The foregoing difference in diameter, it may be noted, is slight, and in any event it should be understood that the chambers may all have the same diameter.

FIG. 9 illustrates two modifications comprising means for improving the thermal conductivity through the cylindrical walls of the absorber and liquid cooler, and means for protecting the absorber, condenser, and liquid cooler against unnecessary temperature rises. The thermal conductivity is improved by the provision of extended surfaces or liners 88, 89 in the absorber and liquid cooler, these being formed of a good heatconducting material such as aluminum, high aluminum alloys, copper, beryllium and high beryllium alloys. As shown, the surfaces have closely spaced alternating ridges 69 and troughs 79, but any other suitable structure or design may be used which extends the area over which the solution makes contact, as note fins in FIG. 5. A screw-threaded interior would be feasible. If desired, such extended surfaces could also be used in the condenser or the other chambers. Their effect is to counter or circumvent the thermal resistance of the solution; thus, where the solution tends to restrict heat flow from the absorber and liquid cooler, owing to its thermal resistance, the extended surfaces 88, 89 of good heat-conducting material act to dissipate the heat and, as described above to be desirable, to keep the absorber and liquid cooler, and especially the solution therein, in a cool state.

A further means of protecting the absorber and liquid cooler, and also the condenser, against undesired heating is shown by the provision of thermal insulation at 104, 107, 109, 111, 119, 180, and 181 of FIG. 9, thus protecting these structures from being heated by heat flow from the heated generator. It will be seen that the liquid cooler is thermally insulated at 104 at the plate (omitted to simplify the showing) which separates it from the generator, and also at 107 at the adjoining edges of the external fins; the absorber is similarly insulated, and the vapor tubes extending therethrough are also insulated at 119; and in the condenser the cylindrical vapor passage is insulated at 180, and the plate separating the condenser from the evaporator is insulated at 181. As indicated, the walls on which the insulation rests have been omitted from FIG. 9 to simplify the showing.

Turning now to FIG. 10, this shows a hollow pipe 1 12 similar to pipe 26 but somewhat lengthened so that it extends closer to the end wall 22. Pitot tube 26 is the same as in FIG. 1, but an oppositely positioned fixed arm 113 has been added having approximately the same dimensions and weight as tube 26. Arm 113 is closed at its end 114. A segment 115 of a magnetizable material, such as iron, is fixedly attached to the end portion of arm 113, and opposite such segment on the outer side of end wall 22, which wall in this case is made of non-magnetic material like aluminum, there is fixed another segment 116 of a magnet. The two segments are preferably of the same dimensions, and are of relatively short length, say up to 3 or 4 inches for a device having the size set forth in the example. Similarly, their width may be up to 2 or 3 inches, and their thickness from k to l or 2 inches. These dimensions are not critical; what is desired is that there shall be an effective magnetic attraction exercised by magnet 116 on the magnetizable segment 115. Referring to FIG. 1 for the moment, and having in mind that the pump and spray assembly 25 is supported on the bearings 34, 35, and that the open end 106 of pitot tube 29 is subjected to the force of the rotating liquid in chamber 14, it may be apparent that some rotary movement of the assembly 25 may take place; but such movement does not create a problem in FIG. 1 because the counterweight 30 stabilizes the assembly sufficiently to permit effective pumping by the pitot tube. But the stabilizing effect of the counterweight, it may be noted, requires the assembly to be in a more or less horizontal position. If the device were to be positioned vertically, as on the end wall 22, then the stabilizing effect of the counterweight would be substantially lost and the pitot tube rendered ineffective for practical purposes. But, referring to FIG. 10, by means of the magnet 116 and the magnetizable segment 115, the pitot tube can be held in an operative position to pump solution, and the counterweight is eliminated. It will, of course, be understood that the strength of the magnet 116, and its proximity to segment 115, are sufficient to attract, slow down, and/or hold the segment 115 to enable the pitot tube to pump the solution. Even if the pitot tube tended to rotate with the chambers, there would be an effective pumping action if the magnetic attraction were sufficient to slow down the tube so that a speed differential existed between the chambers and the tube. Thus, the device of FIG. is independent of its orientation in space.

It will be understood that the positions of the magnetizing and magnetizable segments may be reversed, i.e., the magnet may be on the arm 113 and the magnetizable segment on adjacent wall 22 of the heat pump.

Furthermore, instead of wall 22, there may be used an adjacent portion of the wall 15, as at 15a. Also, a number of segments 116 may be used in a circumferential arrangement to aid in attracting segment 115.

In FIG. 1 1, a modified device is shown which is a consequence of the improvement of FIG. 10 and which takes advantage of the ability to dispose the device in a vertical position. As shown by dashed lines 117 and 117a, the condenser 12, as an alternative or optional construction, may have lateral cylindrical surfaces which taper, the chamber having a narrower diameter at its left hand end than at its right hand end, looking at FIG. 11. Similarly, evaporator 13 may have walls that taper, as shown by the dashed lines 118 and 118a. The device of FIG. 11 is intended to be used in a vertical position with the evaporator at the top and the liquid cooler at the bottom. In both chambers 12 and 13, the flow of liquid through each, during rotation of the device, is aided by the conical shape of the chambers. The better flow means that film thicknesses will be less and in turn heat transfer across the thinner films will be improved.

FIG. 12 is a modification intended to show the miniaturization capability of the invention. This view is drawn more or less to scale and thus itself illustrates the point of miniaturization. It may be seen that the over all length of the device is approximately 1 foot, give or take an inch or two. The device comprises four interconnected units or chambers: generator 120, absorber 121, condenser 122, and evaporator 123, all enclosed by the single cylinder 124 having end walls 125, 126. The chambers as a group are hermetically sealed, as in FIG. 1, and are mounted for rotation. At the right hand end there is an electric motor 127 having a shaft 128 which is fixedly secured to the end wall 125, and the motor is thus able to rotate the chambers as a group. The motor is secured to end wall 129 of the housing 130 by bolts, as shown. At the left hand end the device is rotatably supported on bearing 13] which is mounted in end wall 132 of the housing. The device is thus supported for rotation at each end, i.e., by the motor shaft and by bearing 131. Wall 132 abuts a wall 133, as of a cabinet 134 whose interior it is desired to cool, and it will be seen that evaporator 123 and its fan blades 135 are disposed within the cabinet space. The housing 130 is further defined by upper and lower walls 136, 137, and also by end walls 129 and 132.

The generator 120 is provided with a pump and spray assembly 134 comprising a substantially non-rotating hollow pipe which extends between the generator and the absorber 121 and which at one end is connected to a pitot tube 141 through the hollow arm 142. The latter has an extension 143 to which a counterweight 144 is connected, both preferebly of solid section rather than hollow. Pipe 140 at its other end terminates in an outlet 145 through which refrigerant solution is discharged onto the fan 146, the latter being attached to plate 147. Pipe 140 is supported on the bearing 148 which is also attached to the plate 147.

Absorber 121 is separated from the generator by plate 147 which, as in the case of the FIG. 1 device, is provided with peripheral apertures, two of which are shown at 149, 150. A passageway 151, comprising an offset tube, extends through the absorber with one end 152 opening through plate 147 into the generator and one end 153 opening through plate 154 into the condenser. External fins 155 are present on the absorber.

Condenser 122 is further defined by the plate 154 and by the apertured plate 156, the latter having apertures at the very periphery thereof, two of which are seen at 157 and 158. Plate 147, it may be noted, has its apertures in the peripheral portion, i.e., they are slightly spaced radially inwardly of the periphery. In the condenser, a passageway 159, comprising an offset tube, extends therethrough and has an opening 160 in wall 154 and an opening 161 in plate 156. External fins 162 are provided on the condenser.

The generator is externally wound with electrical resistance wire 163, one end of which is connected by lead 164 to slip ring 165 mounted on motor shaft 128, and the other end of which is connected by lead 166 to slip ring 167 on said shaft. The slip rings are in electrical contact with carbon brushes 168, 169 mounted in the holder 170 from which leads extend to a plug 171 connectable to a receptacle 172. Another plug 173 connects the motor to the receptacle. Bracket 174 supports holder 170 on the wall 129.

In operation, refrigerant solution, such as that described above, may be added to the generator through the axially located pipe 175, after first evacuating the device as described. A cap and valve (not shown) may be connected to pipe 175, as at 59, 60, and 70 of FIG. 1; or pipe 175 may simply have a cap which is removable to permit filling. Filling equipment, note FIG. 8, is used to introduce the solution, and if pipe 175 is capped as described, then a union is used on the right side of valve 59. Then the motor is started to rotate the device, and the solution in the generator is heated by means of coil 163. The resulting vapors pass by opening 152, passage 151, and opening 153 into condenser 122, are condensed, and thecondensed vapors pass by peripheral openings 157, 158 into evaporator 123 where they are vaporized, the vapors then flowing by opening 161, passage 159, and opening 160 to the absorber 121. In the latter the vapors are sprayed by concentrated refrigerant solution delivered to outlet 145 by the pumping action of pitot tube 141. Fan 146, which rotates with wall 147 and the chambers as a group, acts to spray solution throughout the absorber, while the counterweight 144 helps keep the pitot tube in a substantially non-rotating disposition. Diluted refrigerant solution in the absorber flows back to the generator via peripheral openings 149, 150.

In evaporator 123, heat of vaporization is taken up to vaporize the condensed vapors entering therein, thus cooling the walls of the evaporator, including the external surfaces thereof, while fins 135 move air that has been cooled by such surfaces throughout the space to be cooled. Heat is dissipated from the condenser and absorber by the external fins 162 and 155, respectively.

The motor speed in this case will preferably be higher than with the larger device of FIG. 1 and may range from 3,000 to 4,000 r.p.m., say about 3,600 r.p.m. Instead of two electrical plugs 171 and 173, it will be understood that only one may suffice, after making necessary circuit changes. It is considered that the device may be operated on I watts of power, no more than that required by an ordinary light bulb, a feature that makes the device suitable where the power supply is limited.

Suitably, cabinet 134 may contain electronic components that tend to heat up, and the device thus comprises a convenient and inexpensive means of cooling them. It will be understood that in addition to a cabinet like 134, the device may be used to cool any space or article capable of being benefitted thereby. It may be applied to cool a room, or part of one, or be used on a desk or table top, or as a portable air conditioning unit.

In FIG. 12, it is preferred that the absorber 121 be equipped with extended internal surfaces or fins, partly indicated at 176, which are contiguous with wall 124. These surfaces are like those shown at 89 of FIG. 9.

FIG. 13 shows in simplified form a preferred embodiment of the device comprising four units: a conically shaped generator 185, a conically shaped absorber 186, a condenser in the form ofa group ofcircumferentially arranged radially outwardly slanted finned tubes two of which are shown at 187, 188, and a narrow evaporator 189 of rather large diameter. At 190 in the generator is the pump and spray assembly comprising hollow tube 191 having pitot tube 192 adjacent one end and one or more spray nozzles 193 adjacent the other end. Tube 191 rests on bearings 194, 195, the former being inserted in the shaft 196 and the latter in plate 197. At 198 is a counterweight corresponding to 30 of FIG. 1.

The generator is heated by suitable means, such as those described, and the vapors from the solution pass through openings 199, 200 into the condenser tubes 187, 188 where they are condensed, the condensate collecting at traps 201, 202, from which it passes by tubes 203, 204 into the evaporator 189. It is apparent from FIG. 13 that the trap 201 is formed in the angle of tubes 188 and 204. Tubes 203 and 204 are circumferentially arranged, and initially they slant radially inwardly and then radially outwardly to join the evaporator 189.

In the evaporator, the condensate is vaporized, thereby abstracting heat from the evaporator walls and the surrounding air, and the cooled air is distributed by the external fins 205. Vapors pass into the opening 206 of the cylindrical passage 207 and emerge in the absorber 186 where they are absorbed by the sprayed solution coming from nozzle 193. Heat of absorption is dissipated by external fins 219. The sprayed solution, of course, is the concentrated liquid solution from the generator, formed by driving off vapors from the original refrigerant solution. The diluted solution in the absorber collects, as indicated at 208, and is able to flow into the generator through the peripheral openings in plate 197, two of which are seen at 209, 209a; and if desired, a small barrier wall 20% may be present in unit just opposite such openings to form a small liquid trap from which liquid may overflow into unit 185. In the generator, the liquid solution collects as indicated at 210, and is separated, by heating, into the vapors described and into the concentrated liquid solution or fraction which is removed by the pitot tube and sent to the absorber.

The device is rotated and supported at each end by the shafts 196 and 211, each rotatably supported on bearings 212, 213. Pulley drive means are partially shown at 214.

It will be apparent that, as in the case of FIG. 1, when the device is rotating, the pump and spray assembly will remain more or less stationary. Instead of such assembly, the magnetic holding means of FIG. 10 may be used in place thereof, and when this is done, the device will be insensitive to gravity, i.e., it may be operated in the vertical as well as the horizontal position.

The device may also be provided with the insulation shown in FIG. 9, and with the extended surfaces for the absorber as shown in the latter figure.

Besides the advantage of being operable in vertical position, the tapering of the generator and absorber helps to avoid the formation of thick liquid films which reduce heat transfer therethrough. As can be seen, the tapered or conical sides, in cooperation with the rotation, act to drain liquid toward the larger end of these units, thus tending to expose substantially bare wall surfaces, as at 215, 216. At 215 the surface is hot, while at 216 the surface is cold, and in either case heat transfer across the bare unfilmed surfaces is good. Bare surfaces also tend to be exposed in the slanted condenser tubes, promoting efficient condensation of the vapors. The fins 217, 218 on the condenser tubes improve their condensing ability and increase the transfer of heat of condensation to the surrounding air.

The device of FIG. 13 is considered to have a higher pressure to the right of plate 197 and a lower pressure to the left thereof. The high pressure extends into the tubes 187, 188 up to the liquid traps 201, 202. As an example, the high pressure may be on the order of 1 psia and the low pressure about 0.1 psia, or about onetenth of the high pressure. With aqueous solutions, the high pressure may range up to 2 psia or more, and the low pressure from 0.1 to 0.2 psia or more. As in the case of FIG. 1, the two sides are separated to maintain the pressure differential, and it will be noted that the depth of liquid at 208 in the lower pressure absorber will be such as to maintain the separation without preventing necessary flow of liquid into the generator.

In FIG. 13, the evaporator 189 can be made narrower as shown owing to the fact that heat transfer through evaporation is efficient, and consequently a reduction in size is possible. The evaporator can of course be made larger.

The modifications of FIGS. 9, l0, and 11 may be incorporated in any of the devices described herein.

Considering the invention in review, it may be appreciated that in addition to the described advantages of low power costs, improved efficiency, more quiet operation, size reduction and miniaturization, and weight reduction plus good heat transfer stemming from the use of thinner walls, the invention possesses an enhanced utility in being able to use waste heat for heating the generator. This fact enables the device to be used wherever waste heat is available, notably in association with internal combustion engines, including diesel engines, to provide cooling for the passenger compartment of automobiles, trucks, busses, aircraft, and other vehicles, including military vehicles. Hot engine exhaust gases, which are now discharged to atmosphere, may be brought in heat exchange relation with the generator of the described device, while the evaporator may be positioned in a conduit or other passage through which atmospheric air passes to the said compartment. The air is thus cooled as described. Suitably the air blowing over the evaporator surfaces may be the air stream produced by the engine fan. Rotation of the device may be accomplished by a driving belt driven by the engine. Not least of the benefits obtainable is the fact that the device will draw less power from the engine than present air conditioners which employ compressors. Less power drain on the engine also means less pollution by exhaust gases.

Also described was the advantage of portability, one form of a portable device being shown in FIG. 12. The latter device is movable about the premises, or over a desk top, but it relies on a source of electric current, although such source, in view of the low power requirement, could be a battery. For a device of larger size, and capableof being used as a central air conditioner, portability can be realized by using a propane, or other cheap hydrocarbon, burner to heat the generator. A portable package or system can thus be envisaged comprising the air conditioning device, a tank of propane, a propane burner positioned to heat the generator, a small motor to rotate the device, and a light battery to operate the motor. Suitable apertures will be provided to admit air, discharge cooled air, and vent exhaust gases. Considering that propane can provide 20,000 BTU/lb, a tank of 10 lbs. of propane would provide 200,000 BTU. At 50 percent efficiency, 100,000 BTU would be available for air conditioning, and the device could thus remove 1,000 BTU/hr. from air for a period of 100 hours. Such a portable package would be useful to cool a small enclosed pleasure boat, or a remote cabin, or a trailer, or other space remote from electric supply mains. Considering the foregoing data a bit further, it may be noted that 100,000 BTU is equivalent to about 30 kw-hrs. of energy. If one were to take a conventional compressor-operated air conditioner, having a coefficient of performance of 2, and attempt to use it in one of the applications just described, there would be needed a battery providing 15 kw-hrs. of energy. But so far as is known, no such portable batteries are available. If one used a conventional lead-acid battery delivering a nominal 20 watt-hrs./lb., one would need 15,000/20 or 750 lbs. of battery, and this of course would not be portable. A silver-zinc cell delivering watt-hrs./lb. would require 187 lbs. of battery, again a non-portable article.

The invention is capable of obvious variations without departing from its scope.

In the light of the foregoing description, the following is claimed:

1. A heat-operated rotary heat pump for use as an air conditioner comprising a plurality of enclosed, interconnected chambers mounted for rotation as a group, the chambers as a group being airtight and liquidtight and including a generator in which a refrigerant is present and to which heat is applied to convert the refrigerant into vapors and a concentrated liquid fraction;

a condenser to which said vapors are passed for condensation therein, means for passing the vapors from the generator to the condenser;

an evaporator for receiving condensed vapors from the condenser and vaporizing the same, thereby to absorb heat of vaporization and to cool the evaporator walls, means for passing said condensed vapors from the condenser to the evaporator;

an absorber in which said concentrated liquid fraction from the generator is brought in contact with vapors from the evaporator, thereby to absorb said vapors and to form a dilute liquid fraction, means for passing said vapors from the evaporator to the absorber, means for passing said dilute liquid fraction from the absorber to the generator to be concentrated therein;

and a liquid cooler for receiving concentrated liquid fraction from the generator and cooling the same,

means for passing said concentrated liquid fraction from the generator to the liquid cooler, means for pumping cooled concentrated liquid fraction from the liquid cooler to said absorber; the liquid cooler, generator, and absorber, in such order, being disposed next adjacent one another;

said pumping means comprising a hollow pipe extending from the liquid cooler through the generator and into the absorber and having a pitot tube connected to that portion of said pipe in the liquid cooler for picking up cooled concentrated liquid fraction and transferring the same to said pipe, means on that portion of the pipe in the generator for maintaining the pipe in an operative pumping position, means on that portion of the pipe in the absorber for forming a spray of said cooled concentrated liquid fraction introduced thereto from the liquid cooler;

'means for supporting said chambers for rotation, and

means for rotating the chambers as a group;

fan means on the condenser, absorber, and liquid cooler for dissipating heat therefrom, and fan means on the evaporator for moving air against said cooled evaporator walls, thereby to cool said air.

2. A rotary heat pump device for use as an air conditioner comprising a plurality of units including a generator, an absorber disposed in end-to-end relation with the generator, a common wall therebetween, a condenser, and an evaporator, said units as a group being mounted for rotation,

said generator having a refrigerant to which heat is applied to convert the same into vapors and a concentrated liquid fraction, pumping means in the generator for pumping'said liquid fraction to the absorber, said pumping means extending axially in the generator and being supported on and extending through said common wall, and means on said common wall for supporting said pumping means so that said device is rotatable relatively to the pumping means,

means for passing said vapors to the condenser for condensation therein, thereby to release heat of condensation, fins on said condenser for dissipating said heat of condensation, and means for passing condensed vapors to the evaporator,

said evaporator receiving said condensed vapors and vaporizing the same, thereby to absorb heat of vaporization and to cool the evaporator walls and external surfaces thereof, fan blades on the evaporator for moving air in heat exchange relationship with said cooled surfaces, thereby to provide a stream of cooled air, means for passing vapors from the evaporator to the absorber,

means in the absorber for spraying said concentrated liquid fraction therein to facilitate absorption of vapors coming from the evaporator, thereby to form a dilute liquid fraction and to release heat of absorption, fan blades on the absorber to dissipate said heat of absorption, and means comprising an opening in said common wall for passing said dilute liquid fraction to the generator.

3. Device of claim 2 wherein said means for passing vapors to the condenser comprise a plurality of circumferentially spaced tubes which extend through the absorber.

4. Device of claim 2 wherein said means for passing vapors from the evaporator to the absorber comprise an axial passageway which extends through the condenser.

5. Device of claim 2 wherein said pumping means are supported on both end walls of the generator, including said common wall.

6. Device of claim 2 wherein said pumping means comprise a straight hollow pipe extending between the generator and the absorber and having an outlet in the absorber, a pitot tube connected to the pipe for picking up said concentrated liquid fraction and transferring the same to said pipe and to said outlet, and means connected to the pipe for maintaining the same in an operative pumping position.

7. Device of claim 2 wherein a liquid cooler is present to receive concentrated liquid fraction from the generator in order to cool the same before it is passed to the absorber, thereby to improve the efficiency of the absorber.

8. Device of claim 2 wherein said refrigerant is a deliquescent material dissolved in a solvent therefor.

9. Device of claim 2 wherein said refrigerant is an aqueous solution containing at least 50 percent by weight of lithium bromide.

10. Device of claim 2 wherein said refrigerant is a solution of lithium bromide in an alcohol.

11. Device of claim 2 wherein the absorber has means for thermally insulating the same from the generator, thereby to avoid the transfer of heat from the generator to the absorber and to improve the efficiency of the latter, and wherein the condenser has means for thermally insulating the same from the generator and from the evaporator.

12. Device of claim 2 wherein said condenser and evaporator each has a diameter which increases as one moves away from the absorber.

13. A rotary heat pump device for use as an air conditioner comprising a plurality of enclosed units disposed in end-to-end relation comprising a generator, an absorber, a common wall therebetween, a condenser, a common wall between the absorber and condenser, an evaporator, a common wall between the condenser and evaporator, said units as a group being hermetically sealed and mounted for rotation,

said generator having a refrigerant to which heat is applied to convert the refrigerant into vapors and a concentrated liquid fraction, pumping means in the generator for pumping said liquid fraction to the absorber, said pumping means extending axially in the generator and being supported on said common wall between generator and absorber, and means on said last-mentioned common wall for supporting said pumping means so that said device ,is rotatable relatively thereto,

means for passing said vapors to the condenser for condensation therein, thereby to release heat of condensation, fins on said condenser for dissipating said heat of condensation, and means for passing condensed vapors to the evaporator,

said evaporator receiving said condensed vapors and vaporizing the same, thereby to absorb heat of vaporization and to cool the evaporator walls and external surfaces thereof, fan blades on the evaporator for moving air in heat exchange relationship with said cooled surfaces, thereby to provide a stream of cooled air, means for passing vapors from the evaporator to the absorber,

means in the absorber for spraying said concentrated liquid fraction therein to facilitate absorption of vapors coming from the evaporator, thereby to form a dilute liquid fraction and to release heat of absorption, and means for passing said dilute liquid fraction to the generator.

14. Device of claim 13 wherein all of said units are enclosed by an outer cylindrical wall which extends from end to end of the device.

15. Device of claim 13 wherein said spraying means in the absorber are rotatable.

16. A heat-operated miniaturized rotary heat pump for use as an air conditioner comprising a plurality of units including a generator, an absorber, a common wall therebetween, a condenser, and an evaporator, said units as a group being mounted for rotation,

said generator having a refrigerant to which heat is applied to convert the same into vapors and a concentrated liquid fraction, pumping means extending axially in the generator for pumping said liquid fraction to the absorber, said pumping means being supported on and extending through said common wall, and means on the common wall for supporting the pumping means so that said device is rotatable relatively to the pumping means,

means for passing vapors to the condenser for condensation therein, thereby to release heat of condensation, fins on said condenser for dissipating said heat of condensation, and means for passing condensed vapors to the evaporator,

said evaporator receiving said condensed vapors and vaporizing the same, thereby to absorb heat of vaporization and to cool the evaporator walls and external surfaces thereof, fan blades on the evaporator for moving air in heat exchange relationship with said cooled surfaces, thereby to provide a stream of cooled air, means for passing vapors from the evaporator to the absorber,

means in the absorber for spraying said concentrated liquid fraction therein to facilitate absorption of vapors coming from the evaporator, thereby to form a dilute liquid fraction and to release heat of absorption, fan blades on the absorber to dissipate said heat of absorption, and means for passing said dilute liquid fraction to the generator,

a housing for said generator, absorber, and condenser, an electric motor supported on one side of the housing and outwardly of the same and having a shaft which extends to and engages said generator for rotating said units, said evaporator extending beyond said opposite side of the housing into a space to be cooled, and fan means on the evaporator for moving air against said cooled evaporator walls and into said space,

an electric winding around the outside of the generator for heating the same, a pair of slip rings on said shaft to which the winding is connected, and a pair of electric conductors slidably engaging the slip rings and being connectable to an electric current supply. 17. Heat pump of claim 16 having an over all length of approximately l foot.

18. A rotary heat pump device for use as an air conditioner comprising a plurality of units including a generator, an absorber, a common wall therebetween, a condenser, and an evaporator, said units as a group being mounted for rotation, said generator and absorber each having a diameter that increases as one moves away from theevaporator,

said generator having a refrigerant to which heat is applied to convert the same into vapors and a concentrated liquid fraction, pumping means in the generator for pumping said liquid fraction to the absorber, said pumping means extending axially in the generator and through said common wall, and means on both end walls of the generator for supporting said pumping means so that said device is rotatable relatively to the pumping means, means for passing said vapors to the condenser for condensation therein comprising a plurality of circumferentially spaced tubes which extend through the absorber, thereby to release heat of condensation, said condenser comprising a group of circumferentially spaced finned tubes, and means for passing condensed vapors to the evaporator, said evaporator receiving said condensed vapors and vaporizing the same, thereby to absorb heat of vaporization and to cool the evaporator walls and external surfaces thereof, fan blades on the evaporator for moving air in heat exchange relationship with said cooled surfaces, thereby to provide a stream of cooled air, means for passing vapors from the evaporator to the absorber comprising an axial passageway which extends through the condenser,

means in the absorber for dispersing said concentrated liquid fraction therein to facilitate absorption of vapors coming from the evaporator, thereby to form a dilute liquid fraction and to release heat of absorption, fan blades on the absorber to dissipate said heat of absorption, and means for passing said dilute liquid fraction to the generator.

19. Device of claim 18 wherein said finned tubes of the condenser are extensions of the circumferentially spaced tubes which pass through the absorber.

20. Device of claim 18 wherein said finned tubes of the condenser are slanted radially outwardly.

21. Device of claim 20 wherein said finned tubes of the condenser change direction and slant radially inwardly, each tube thus having an angle formed therein which functions as a trap to hold condensed vapors. 

1. A heat-operated rotary heat pump for use as an air conditioner comprising a plurality of enclosed, interconnected chambers mounted for rotation as a group, the chambers as a group being airtight and liquidtight and including a generator in which a refrigerant is present and to which heat is applied to convert the refrigerant into vapors and a concentrated liquid fraction; a condenser to which said vapors are passed for condensation therein, means for passing the vapors from the generator to the condenser; an evaporator for receiving condensed vapors from the condenser and vaporizing the same, thereby to absorb heat of vaporization and to cool the evaporator walls, means for passing said condensed vapors from the condenser to the evaporator; an absorber in which said concentrated liquid fraction from the generator is brought in contact with vapors from the evaporator, thereby to absorb said vapors and to form a dilute liquid fraction, means for passing said vapors from the evaporator to the absorber, means for passing said dilute liquid fraction from the absorber to the generator to be concentrated therein; and a liquid cooler for receiving concentrated liquid fraction from the generator and cooling the same, means for passing said concentrated liquid fraction from the generator to the liquid cooler, means for pumping cooled concentrated liquid fraction from the liquid cooler to said absorber; the liquid cooler, generator, and absorber, in such order, being disposed next adjacent one another; said pumping means comprising a hollow pipe extending from the liquid cooler through the generator and into the absorber and having a pitot tube connected to that portion of said pipe in the liquid cooler for picking up cooled concentrated liquid fraction and transferring the same to said pipe, means on that portion of the pipe in the generator for maintaining the pipe in an operative pumping position, means on that portion of the pipe in the absorber for forming a spray of said cooled concentrated liquid fraction introduced thereto from the liquid cooler; means for supporting said chambers for rotation, and means for rotating the chambers as a group; fan means on the condenser, absorber, and liquid cooler for dissipating heat therefrom, and fan means on the evaporator for moving air against said cooled evaporator walls, thereby to cool said air.
 2. A rotary heat pump device for use as an air conditioner comprising a plurality of units including a generator, an absorber disposed in end-to-end relation with the generator, a common wall therebetween, a condenser, and an evaporator, said units as a group being mounted for rotation, said generator having a refrigerant to which heat is applied to convert the same into vapors and a concentrated liquid fraction, pumping means in the generator for pumping said liquid fraction to the absorber, said pumping means extending axially in the generator and being supported on and extending through said common wall, and means on said common wall for supporting said pumping means so that said device is rotatable relatively to the pumping means, means for passing said vapors to the condenser for condensation therein, thereby to release heat of condensation, fins on said condenser for dissipating said heat of condensation, and means for passing condensed vapors to the evaporator, said evaporator receiving said condensed vapors and vaporizing the same, thereby to absorb heat of vaporizatIon and to cool the evaporator walls and external surfaces thereof, fan blades on the evaporator for moving air in heat exchange relationship with said cooled surfaces, thereby to provide a stream of cooled air, means for passing vapors from the evaporator to the absorber, means in the absorber for spraying said concentrated liquid fraction therein to facilitate absorption of vapors coming from the evaporator, thereby to form a dilute liquid fraction and to release heat of absorption, fan blades on the absorber to dissipate said heat of absorption, and means comprising an opening in said common wall for passing said dilute liquid fraction to the generator.
 3. Device of claim 2 wherein said means for passing vapors to the condenser comprise a plurality of circumferentially spaced tubes which extend through the absorber.
 4. Device of claim 2 wherein said means for passing vapors from the evaporator to the absorber comprise an axial passageway which extends through the condenser.
 5. Device of claim 2 wherein said pumping means are supported on both end walls of the generator, including said common wall.
 6. Device of claim 2 wherein said pumping means comprise a straight hollow pipe extending between the generator and the absorber and having an outlet in the absorber, a pitot tube connected to the pipe for picking up said concentrated liquid fraction and transferring the same to said pipe and to said outlet, and means connected to the pipe for maintaining the same in an operative pumping position.
 7. Device of claim 2 wherein a liquid cooler is present to receive concentrated liquid fraction from the generator in order to cool the same before it is passed to the absorber, thereby to improve the efficiency of the absorber.
 8. Device of claim 2 wherein said refrigerant is a deliquescent material dissolved in a solvent therefor.
 9. Device of claim 2 wherein said refrigerant is an aqueous solution containing at least 50 percent by weight of lithium bromide.
 10. Device of claim 2 wherein said refrigerant is a solution of lithium bromide in an alcohol.
 11. Device of claim 2 wherein the absorber has means for thermally insulating the same from the generator, thereby to avoid the transfer of heat from the generator to the absorber and to improve the efficiency of the latter, and wherein the condenser has means for thermally insulating the same from the generator and from the evaporator.
 12. Device of claim 2 wherein said condenser and evaporator each has a diameter which increases as one moves away from the absorber.
 13. A rotary heat pump device for use as an air conditioner comprising a plurality of enclosed units disposed in end-to-end relation comprising a generator, an absorber, a common wall therebetween, a condenser, a common wall between the absorber and condenser, an evaporator, a common wall between the condenser and evaporator, said units as a group being hermetically sealed and mounted for rotation, said generator having a refrigerant to which heat is applied to convert the refrigerant into vapors and a concentrated liquid fraction, pumping means in the generator for pumping said liquid fraction to the absorber, said pumping means extending axially in the generator and being supported on said common wall between generator and absorber, and means on said last-mentioned common wall for supporting said pumping means so that said device is rotatable relatively thereto, means for passing said vapors to the condenser for condensation therein, thereby to release heat of condensation, fins on said condenser for dissipating said heat of condensation, and means for passing condensed vapors to the evaporator, said evaporator receiving said condensed vapors and vaporizing the same, thereby to absorb heat of vaporization and to cool the evaporator walls and external surfaces thereof, fan blades on the evaporator for moving air in heat exchange relationship with said cooled surfaces, thereby to provide a stream of cooled air, means for pAssing vapors from the evaporator to the absorber, means in the absorber for spraying said concentrated liquid fraction therein to facilitate absorption of vapors coming from the evaporator, thereby to form a dilute liquid fraction and to release heat of absorption, and means for passing said dilute liquid fraction to the generator.
 14. Device of claim 13 wherein all of said units are enclosed by an outer cylindrical wall which extends from end to end of the device.
 15. Device of claim 13 wherein said spraying means in the absorber are rotatable.
 16. A heat-operated miniaturized rotary heat pump for use as an air conditioner comprising a plurality of units including a generator, an absorber, a common wall therebetween, a condenser, and an evaporator, said units as a group being mounted for rotation, said generator having a refrigerant to which heat is applied to convert the same into vapors and a concentrated liquid fraction, pumping means extending axially in the generator for pumping said liquid fraction to the absorber, said pumping means being supported on and extending through said common wall, and means on the common wall for supporting the pumping means so that said device is rotatable relatively to the pumping means, means for passing vapors to the condenser for condensation therein, thereby to release heat of condensation, fins on said condenser for dissipating said heat of condensation, and means for passing condensed vapors to the evaporator, said evaporator receiving said condensed vapors and vaporizing the same, thereby to absorb heat of vaporization and to cool the evaporator walls and external surfaces thereof, fan blades on the evaporator for moving air in heat exchange relationship with said cooled surfaces, thereby to provide a stream of cooled air, means for passing vapors from the evaporator to the absorber, means in the absorber for spraying said concentrated liquid fraction therein to facilitate absorption of vapors coming from the evaporator, thereby to form a dilute liquid fraction and to release heat of absorption, fan blades on the absorber to dissipate said heat of absorption, and means for passing said dilute liquid fraction to the generator, a housing for said generator, absorber, and condenser, an electric motor supported on one side of the housing and outwardly of the same and having a shaft which extends to and engages said generator for rotating said units, said evaporator extending beyond said opposite side of the housing into a space to be cooled, and fan means on the evaporator for moving air against said cooled evaporator walls and into said space, an electric winding around the outside of the generator for heating the same, a pair of slip rings on said shaft to which the winding is connected, and a pair of electric conductors slidably engaging the slip rings and being connectable to an electric current supply.
 17. Heat pump of claim 16 having an over all length of approximately 1 foot.
 18. A rotary heat pump device for use as an air conditioner comprising a plurality of units including a generator, an absorber, a common wall therebetween, a condenser, and an evaporator, said units as a group being mounted for rotation, said generator and absorber each having a diameter that increases as one moves away from the evaporator, said generator having a refrigerant to which heat is applied to convert the same into vapors and a concentrated liquid fraction, pumping means in the generator for pumping said liquid fraction to the absorber, said pumping means extending axially in the generator and through said common wall, and means on both end walls of the generator for supporting said pumping means so that said device is rotatable relatively to the pumping means, means for passing said vapors to the condenser for condensation therein comprising a plurality of circumferentially spaced tubes which extend through the absorber, thereby to release heat of condensation, said condenser compRising a group of circumferentially spaced finned tubes, and means for passing condensed vapors to the evaporator, said evaporator receiving said condensed vapors and vaporizing the same, thereby to absorb heat of vaporization and to cool the evaporator walls and external surfaces thereof, fan blades on the evaporator for moving air in heat exchange relationship with said cooled surfaces, thereby to provide a stream of cooled air, means for passing vapors from the evaporator to the absorber comprising an axial passageway which extends through the condenser, means in the absorber for dispersing said concentrated liquid fraction therein to facilitate absorption of vapors coming from the evaporator, thereby to form a dilute liquid fraction and to release heat of absorption, fan blades on the absorber to dissipate said heat of absorption, and means for passing said dilute liquid fraction to the generator.
 19. Device of claim 18 wherein said finned tubes of the condenser are extensions of the circumferentially spaced tubes which pass through the absorber.
 20. Device of claim 18 wherein said finned tubes of the condenser are slanted radially outwardly.
 21. Device of claim 20 wherein said finned tubes of the condenser change direction and slant radially inwardly, each tube thus having an angle formed therein which functions as a trap to hold condensed vapors. 